This invention relates to methods of forming conductive connections in semiconductor processing.
Semiconductor wafer processing in the fabrication of integrated circuitry typically includes the formation of contact openings within insulating layers to underlying conductive structures. Currently, such processing is typically conducted by photolithography wherein a masking layer is deposited and a desired pattern of openings is formed therethrough. The masking layer is then used as a mask while chemical etching is conducted through the mask openings into the underlying insulative material to etch it largely selective to the masking layer. Thereby, the openings can be extended through the insulating material to the conductive structures therebeneath.
One type of existing conductive structure comprises a field effect transistor gate construction having an insulative silicon nitride cap which overlies a conductive elemental tungsten layer which overlies a conductive WNv layer which overlies a lesser conductive WxSiyNz layer which overlies a conductively doped polysilicon layer which overlies a gate dielectric layer. One or more insulating layers typically overlies such constructions. It is typically desirable to make conductive electrical connections to such structures, preferably completely through such layers to contact the conductively doped polysilicon.
The following invention was motivated in making electrical contacts to such constructions, although such is in no way so limited. The invention is limited only by the accompanying claims as literally worded without limiting reference to the specification, and in accordance with the doctrine of equivalents.
The invention includes a semiconductor processing method of forming a conductive connection. In one implementation, a conductive structure is formed over a substrate, with the conductive structure including a conductively doped semiconductive material and an overlying WxSiyNz comprising material, where each of xe2x80x9cxxe2x80x9d, xe2x80x9cyxe2x80x9d and xe2x80x9czxe2x80x9d is greater than zero. Insulative material is formed over the WxSiyNz comprising material of the conductive structure. A contact opening is etched through the insulative material and through the WxSiyNz material effective to expose the conductively doped semiconductive material. The contact opening etching includes at least one dry etch, followed by at least one wet etch, followed by at least one dry etch. At least one wet etch occurs before etching the WxSiyNz comprising material. After the contact opening etching, conductive material is formed within the contact opening in electrical connection with the conductively doped semiconductive material.
In one implementation, a semiconductor processing method of forming a conductive connection includes forming a conductive structure over a substrate, with the conductive structure comprising a conductively doped semiconductive material and a conductive tungsten comprising material overlying the conductively doped semiconductive material. The conductive tungsten comprising material comprises at least one of elemental tungsten, a tungsten alloy, and WNv where xe2x80x9cvxe2x80x9d is greater than zero. Insulative material is formed over the conductive tungsten comprising material. A contact opening is etched into the insulative material to proximate the conductive tungsten comprising material. After etching the insulative material, the conductive tungsten comprising material is wet etched effective to extend the contact opening to therewithin. After the wet etching, conductive material is formed within the contact opening in electrical connection with the conductively doped semiconductive material.